There is also a slack channel as at 2015-09-04. Information can be found here Less_Wrong_Slack

(Note that this isn't an official channel. Actually, my experience tends to indicate that having a regular IRC channel might well be Considered Harmful in terms of how much of the reader's life force it will suck out.) --Eliezer Yudkowsky 02:56, 11 February 2010 (UTC))